It was easy to nod in proud agreement when Bruce Arena, almost immediately upon taking over as U.S. men’s national team manager last November, quickly scratched out a list of his top 50 players. A sizeable player pool coming right off the top of his head seemed to validate suspicions: the U.S. was in a very good place -- maybe the best place ever.

While the pool looked shallow in elite game-changers, it seemed pleasingly stocked with competent old hands and even more so with emerging young bucks like Emerson Hyndman, Matt Miazga and Cameron Carter-Vickers. There even seemed to be a growing line of MLS men capable of becoming full internationals.

Then came the CONCACAF Gold Cup.

And now seems fair to wonder: Did the optimists who saw a bounty of depth simply have it wrong?

The United States is through to the Gold Cup elimination rounds, which was always the minimum standard for this relatively inconsequential tournament, the real payout here being what we could learn. Arena said as much, prioritizing roster building ahead of Russia 2018.

Now, reinforcements have arrived, which is good news for anyone desperate to see the United States sweep away with a Gold Cup crown, for whatever that’s worth.

STEVE DAVIS

But in the bigger picture, in a tournament where U.S. depth would be featured, count most of us as underwhelmed, to say the least. The question now: Is this cause for alarm or just a hurdle to be dealt with?

The clear evidence thus far

Even with a B-minus team, a draw with Panama and a squeaker over tiny Martinique was disappointing. The Yanks did beat Nicaragua, 3-0, although the needed third goal came with only nine opponents on the field.

Remember the golden rule of assessing friendlies or, in this case, tournaments of lesser consequence: Players can keep themselves in the conversation, but can’t fully establish themselves as World Cup roster threats. But they certainly can play their way out of consideration. If they can’t step up here, on home soil, they aren’t likely to take a World Cup by storm.

As for making an impression, none of the “trialists” made much of one.

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Kelyn Rowe came closest with a goal and an assist, plus plenty of moments to suggest he understood this particular tournament’s dynamics: that a lot of guys are getting their shot, so playing it safe was no recipe for success.

Dom Dwyer did his thing and nailed a nice goal. On the other hand, his thing can be a mixed bag; he scores goals and gives defenders lots to handle, no doubt, but he’s also foul-prone and blessed with no better than an average first touch.

Joe Corona mostly played it safe. Cristian Roldan didn’t look ready. Dax McCarty demonstrated a big gap between him and Michael Bradley. Neither Eric Lichaj nor Graham Zusi grabbed the chance to ensconce himself as DeAndre Yedlin’s backup at right back. Same for Justin Morrow on the other side (while the presumed starter, Jorge Villafana, teetered a bit, too.)

In fact, no one along the back line distinguished himself. Behind them, even Brad Guzan allowed a questionable goal.

How did we get here?

Depth is so critical, because runs of injury and bad form happen. Remember not too long ago that seven potential starters were suddenly unavailable for a must-win World Cup qualifier against Honduras.

Limited depth in the pool also proved troublesome in 2014. Jozy Altidore’s injury left the team without a like-for-like replacement, demonstrating the importance in depth across all positions. You just never know which spot may go suddenly threadbare.

GRAHAM PARKER

Building depth after a World Cup cycle is the logical place to start. Two years ago, at the 2015 Gold Cup, for instance, seemed like a swell place for then-coach Jurgen Klinsmann to mix and match a few more newbies with a strategic balance of internationally-tested types.

Instead, Guzan, Timothy Chandler, Kyle Beckerman, Mix Diskerud and Chris Wondolowski were among those who played prominent roles following 2014 World Cup appearances. A small selection of relatively new faces did feature, Gyasi Zardes and the rising Yedlin, for instance. But there were too many familiar faces who didn’t look like they’d be part of the picture for 2018.

Moving forward, Klinsmann remained determined to shoehorn Jermaine Jones into the rotation. And he couldn’t divest himself from Dempsey as a central building block. The point is, as team reboots go, Klinsmann’s wasn’t much of one.

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No disrespect to the aforementioned guys, but each time someone in the 30-plus crowd started in 2015 and 2016, it subtracted a chance to see a Rowe or a Paul Arriola. By the time Arena took charge last November, there was something of a bottleneck, a build-up of younger guys eager for their chance.

So over the last year or so, when we all spoke of U.S. depth being in a good place, it was often on speculation or perhaps based too heavily on appearances in meaningless friendlies.

Just missing pieces? Or something more?

There’s no question that assessing a larger group of relative newbies, on the field together, likely less confident and perhaps desperate for leaders, will be less definitive than sprinkling them in gradually.

Would Dwyer be more effective playing alongside an internationally experienced strike partner? Would Corona probe more aggressively for vertical, key passes with a more experienced No. 8 behind him? Would wide players more faithfully stretch the field horizontally when joined by two highly capable interior midfielders? It’s all hard to say.

Or take a guy like Kellyn Acosta, who hasn’t shined so far. Acosta’s upside at this point shouldn’t be defined by what he does when asked to be the guy in midfield, but rather by how he performs in a supporting role. So we’ll all be interested to see his next chance alongside Bradley.

It’s not like the United States depth is in a bad place. But 270 minutes of what should have been a manageable Gold Cup have told us this: It’s harder to be confident in the immediate set of U.S. back-ups.